1. Field of the Invention
The invention relates to quick release mechanisms for joining two members under tension.
2. Description of the Related Art
There are numerous situations where it is desirable to have a fast reliable means for releasing two members joined together under tension. Releasing gliders from tow airplanes, releasing barges from tugboats, sails or spinnakers from sailboats, are just a few of the many places where this need is encountered. There are equally as many applications where it is desirable to have two members under tension release when the tension force reaches a preselected level. Thus, the mechanism in this case would be functioning as a "weak link", such as that required in a ski boot binding mechanism. Moreover, it is highly desirable that normal wear and tear of the mechanism not appreciably effect the releasing characteristics of the device within the useful life span of the apparatus.
Various mechanisms have been designed for sailboat rigging to release two members joined together. The simplest is the so-called "pelican" fitting (named for its appearance) which is particularly difficult to release once under strong tension. The Wichard Company of France has improved upon that simple design by providing a swivel point of attachment for one line and a spring released locking bar to unlatch the other member. However, when this device is under heavy tension, a lanyard must be attached to the locking bar in order to be able to apply sufficient force to release the mechanism.
U.S. Pat. No. 4,944,074, issued to Bullat et al. on Jul. 31, 1990, discloses a quick release mechanism that is designed to release when a predetermined tension is exerted between two members. This device works by having a sphere, which is attached to one member, pull free from a cylindrical spring housing, which is attached to the other member, when the desired tension force is reached. The force required to release the sphere is a function of the slits designed into the cylindrical spring housing as well as materials used in construction of the housing and sphere. Reloading after release requires releasing the sphere from its member and re-inserting the sphere within the housing or threading the member through the housing until the sphere is properly seated. Either method is inconvenient. Also, this device does not disclose a mechanism that can be adapted to be released by hand.